Doping heteroatoms on carbon materials could bring some special advantages for using as catalyst support.In this work, a boron doped lamellar porous carbon(B-LPC) was prepared facilely and utilized as carbonbased supp...Doping heteroatoms on carbon materials could bring some special advantages for using as catalyst support.In this work, a boron doped lamellar porous carbon(B-LPC) was prepared facilely and utilized as carbonbased support to construct Cu/B-LPC catalyst for dimethyl oxalate(DMO) hydrogenation. Doping boron could make the B-LPC own more defects on surface and bigger pore size than B-free LPC, which were beneficial to disperse and anchor Cu nanoparticles. Moreover, the interaction between Cu species and B-LPC could be strengthened by the doped B, which not only stabilized the Cu nanoparticles, but also tuned the valence of Cu species to maintain more Cu^(+). Therefore, the B-doped Cu/B-LPC catalyst exhibited stronger hydrogenation ability and obtained higher alcohols selectivity than Cu/LPC, as well as high stability without decrease of DMO conversion and ethylene glycol selectivity even after 300 h of reaction at 240℃.展开更多
Dimethyl oxalate(DMO) hydrogenation is a crucial step in the coal to ethylene glycol(CTEG) process.Herein, Cu catalyst supported on fibrous mesoporous silica(Cu/FMS) was synthesized via liquid phase deposition techniq...Dimethyl oxalate(DMO) hydrogenation is a crucial step in the coal to ethylene glycol(CTEG) process.Herein, Cu catalyst supported on fibrous mesoporous silica(Cu/FMS) was synthesized via liquid phase deposition technique and applied for the DMO hydrogenation to EG. The catalyst exhibited a remarkable EG selectivity of 96.95% and maintained its activity without deactivation for 1000 h. Fibers of FMS support and liquid phase deposition technology cooperated to give high dispersion of Cu species in the Cu/FMS catalyst, resulting in a high Cu surface area. The formation of Si—O—Cu during catalyst preparation process increased the Cu^(+)/(Cu^(0)+ Cu^(+)) ratio and enhanced the thermal and valence stability of Cu species.The high Cu^(+) surface area and Cu stability(thermal and valence stability) of the Cu/FMS catalyst were key factors for achieving superior EG selectivity and ultra-high stability.展开更多
The purpose of this study was to prepare iron-based catalysts supported on silica by autocombustion method for directly using for Fischer-Tropsch synthesis(FTS) without a reduction step. The effect of different citr...The purpose of this study was to prepare iron-based catalysts supported on silica by autocombustion method for directly using for Fischer-Tropsch synthesis(FTS) without a reduction step. The effect of different citric acid(CA):iron nitrate(N) molar ratios and acid types on the FTS performance of catalysts were investigated. The CA:N molar ratios had an important influence on the formation of iron active phases and FTS activity. The iron carbide(FexC), which is known to be one of the iron active phases, was demonstrated by the X-ray diffraction and X-ray photoelectron spectroscopy. Increasing the CA:N molar ratios up to 0.1 increased CO conversion of catalyst to 86.5%, which was then decreased markedly at higher CA:N molar ratios. An excess of CA resulted in carbon residues covering the catalyst surface and declined FTS activity. The optimal catalyst(CA:N molar ratio = 0.1) achieved the highest CO conversion when compared with other autocombustion catalysts as well as reference catalyst prepared by impregnation method, followed by a reduction step. The autocombustion method had the advantage to synthesize more efficient catalysts without a reduction step. More interestingly, iron-based FTS catalysts need induction duration at the initial stage of FTS reaction even after reduction, because metallic iron species need time to be transformed to FexC. But here, even if without reduction, FexC was formed directly by autocombustion and induction period was eliminated during FTS reaction.展开更多
基金financially supported by the National Natural Science Foundation of China (22008166)Natural Science Foundation of Shanxi (201901D211047)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi (2019L0185)。
文摘Doping heteroatoms on carbon materials could bring some special advantages for using as catalyst support.In this work, a boron doped lamellar porous carbon(B-LPC) was prepared facilely and utilized as carbonbased support to construct Cu/B-LPC catalyst for dimethyl oxalate(DMO) hydrogenation. Doping boron could make the B-LPC own more defects on surface and bigger pore size than B-free LPC, which were beneficial to disperse and anchor Cu nanoparticles. Moreover, the interaction between Cu species and B-LPC could be strengthened by the doped B, which not only stabilized the Cu nanoparticles, but also tuned the valence of Cu species to maintain more Cu^(+). Therefore, the B-doped Cu/B-LPC catalyst exhibited stronger hydrogenation ability and obtained higher alcohols selectivity than Cu/LPC, as well as high stability without decrease of DMO conversion and ethylene glycol selectivity even after 300 h of reaction at 240℃.
基金financially supported by National Natural Science Foundation of China (22008166)Natural Science Foundation of Shanxi (201901D211047)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi (2019L0185)。
文摘Dimethyl oxalate(DMO) hydrogenation is a crucial step in the coal to ethylene glycol(CTEG) process.Herein, Cu catalyst supported on fibrous mesoporous silica(Cu/FMS) was synthesized via liquid phase deposition technique and applied for the DMO hydrogenation to EG. The catalyst exhibited a remarkable EG selectivity of 96.95% and maintained its activity without deactivation for 1000 h. Fibers of FMS support and liquid phase deposition technology cooperated to give high dispersion of Cu species in the Cu/FMS catalyst, resulting in a high Cu surface area. The formation of Si—O—Cu during catalyst preparation process increased the Cu^(+)/(Cu^(0)+ Cu^(+)) ratio and enhanced the thermal and valence stability of Cu species.The high Cu^(+) surface area and Cu stability(thermal and valence stability) of the Cu/FMS catalyst were key factors for achieving superior EG selectivity and ultra-high stability.
基金financial support to the Overseas Academic Presentation Scholarship for Graduate Students, Graduate School, Chulalongkorn University
文摘The purpose of this study was to prepare iron-based catalysts supported on silica by autocombustion method for directly using for Fischer-Tropsch synthesis(FTS) without a reduction step. The effect of different citric acid(CA):iron nitrate(N) molar ratios and acid types on the FTS performance of catalysts were investigated. The CA:N molar ratios had an important influence on the formation of iron active phases and FTS activity. The iron carbide(FexC), which is known to be one of the iron active phases, was demonstrated by the X-ray diffraction and X-ray photoelectron spectroscopy. Increasing the CA:N molar ratios up to 0.1 increased CO conversion of catalyst to 86.5%, which was then decreased markedly at higher CA:N molar ratios. An excess of CA resulted in carbon residues covering the catalyst surface and declined FTS activity. The optimal catalyst(CA:N molar ratio = 0.1) achieved the highest CO conversion when compared with other autocombustion catalysts as well as reference catalyst prepared by impregnation method, followed by a reduction step. The autocombustion method had the advantage to synthesize more efficient catalysts without a reduction step. More interestingly, iron-based FTS catalysts need induction duration at the initial stage of FTS reaction even after reduction, because metallic iron species need time to be transformed to FexC. But here, even if without reduction, FexC was formed directly by autocombustion and induction period was eliminated during FTS reaction.